Perforating gun assemblies are used to generate holes in steel casing pipe/tubing and/or cement lining in a wellbore to gain access to the oil and/or gas formation. During the process of perforating the oil and/or gas formation, the perforating gun assembly is lowered into and positioned properly in the wellbore. Typical perforating gun assemblies include a carrier and a plurality of shaped charges housed in the carrier. The shaped charges are initiated to create holes in the casing and to blast through the formation so that the hydrocarbons can flow through the casing. Each shaped charge is connected to each other via a detonation cord. The detonation cord is typically coupled to a detonator, such as percussion detonator or an electrical detonator. Electrical detonators typically include hot-wire detonators, semiconductor bridge detonators, or exploding foil initiator (EFI) detonators. Once the detonator is activated/initiated, the detonator begins a sequence of events that initiate the detonation cord, and thereby the shaped charges of the perforation gun assembly.
The perforating gun assembly may spend some time in the fluid-filled environment of the wellbore prior to the initiation of the detonator, and thus the shaped charges. If the gun assembly develops a leak which allows wellbore fluids to enter the perforating gun assembly, several undesirable things may occur, including severe damage to the perforating gun assembly. The assembly may misfire, only partially fire, fire low-order and thereby split/burst open and plug/obstruct the wellbore, and the like.
In view of the continually increasing safety requirements and the problems described hereinabove, there is a need for a detonator for use in a perforating gun system that provides additional precaution against the firing of the perforating gun system when there is a potential leakage of fluid in the perforating gun system. Furthermore, there is a need for a detonator this is capable of being fluid-disabled/fluid desensitized in the presence of fluids in the perforating gun system. Additionally, there is a need for a detonator that facilitates the entry of fluids into the detonator to abort the firing sequence of the perforating gun system.